Coloring images (I am just not good at)
rub-ons - I used some the other day and I was rubbing forever and I could not get it to come off the backing
Although I love glitter I also loathe it because the clean up is such a pain - I use glitter on a card or project and end up covered in it.

I am sure I have more to add to each catagory but it is getting late and I can't think straight. LOL!